Well since Andariel is dead/banished the Sisterhood of the Sighless Eye can flourish again. Wouldn't it make sense for a Rogue to be one of the remaining classes? A ranged character is missing from the roster and a rogue would fit well. Maybe it could be a rogue in training or apprentice.
Of course the only problem is the gender choice they announced for D3. A male rogue is unheard of